The present invention relates to forms which are used for receiving concrete, and, in particular, to a connecting member which is used in such a form.
The general type of form which is used in the present invention has been known and used for some time. It includes two lightweight panels (preferably made of polymeric foam) which are connected together by connecting members to form a block which can be stacked with other, identical blocks, to make a hollow wall that can be filled with concrete. The panels are aligned so that continuous vertical and horizontal concrete beams are formed when the concrete is poured into the forms. Once the concrete has been poured, the lightweight panels and the connectors remain in the wall. The lightweight panels then provide insulation, and the connectors provide a structure to which gypsum board or other finishes can be attached.
In the past, there have been several difficulties with these blocks. One problem is that the blocks sometimes separate or "float" when they are being filled with concrete, which can put them out of proper alignment and allow concrete to leak through the space between blocks. This can create serious problems. To solve this problem, the blocks have been wired together or glued together, but sometimes there still is a problem with float. Once the wall is full of concrete, it is impossible to shift the blocks back into proper position. The problem then is remedied as much as possible by trimming the wall after the concrete has set up.
Another problem involves attaching materials to the outside of the wall after it is poured. The connectors usually provide the material to which drywall, bricks, or other finish material are fastened. In the prior art, the connectors have been made of metal. Since metal is a good conductor of heat, the connectors have typically not extended all the way to the exterior of the wall. A bit of foam has been left on the outside of the connectors, so that the foam serves as an insulator. However, when the connectors are completely embedded in foam, the connectors are not visible, and the people who add the wall finishings may have some difficulty finding the connectors to which they have to attach the finish materials.
Since the connectors cannot be seen from the outside of the wall, it is also impossible to tell at a glance whether the blocks have been stacked correctly so as to provide a continuous concrete beam in the finished structure. If there has been an error in stacking the blocks and there is not a continuous concrete beam, the strength of the structure can be compromised.
In many prior art connectors, the attachment portion of the connector does not extend the full height of the block, so there are gaps in the attachment portion where, if someone tries to put in a screw to hold on drywall or other finish materials, there is nothing to receive the screw.
Also, in order to make the metal connectors lightweight enough so that the blocks are not too heavy, and to make them so that they can easily be pierced by screws for attaching finish materials to the walls, the metal connectors are made of very thin sheet metal material. That means that, in general, only a single thread of the screw is in contact with the metal connector. If there are forces on the finish material which cause it to shift up and down or side to side relative to the metal connector, the screw can enlarge the hole in the metal connector and become loose. Also, if the construction is near the ocean or in another environment in which corrosion is likely, it is possible for the metal connector to corrode so that the connection between the finish material and the wall becomes loose.
Another problem with prior art connectors is that they tend to have relatively small holes through which the concrete has to flow when the wall is being poured. These small holes can impede the flow of the concrete, making it difficult to completely fill the wall with concrete. Air pockets in the concrete can compromise the integrity of the finished wall.
Another problem with the prior art blocks is that, when a horizontal reinforcing bar is added to the block before the concrete is poured, there is generally no good way to be sure the reinforcing bar ends up in the right place to provide the proper reinforcement for the finished wall. The reinforcing bar usually just lies on top of a connector, so the bar ends up at the bottom of a horizontal concrete beam. This is usually not the ideal position for the reinforcing bar to provide the most strength to the wall.